WOW. Back in 1974, whilst at school I used to build these multivibrators using a pair of bc107s and filament MES bulbs as the collector loads. The other values were exact and this really takes me back down memory lane. You can tell how old someone is by asking them what various part numbers mean.
In 1970 I built a multivibrator like this , except that it was with 2 germany PNP "AC 128" transistors. Instead of LED I employed a VW Beetle courtesy light bulb , thus it had to run slower to see light blinking. I had nearly no experience with electronics , so a friend of mine who owned a Radio\ TV repair shop taught me some lessons.
NPN transistor multivibrator was one of the first electronic circuits I ever built, both with an incandescent lamp and a LED. It was a lot of fun to see it work, though I would have to wait over a decade until I got my first scope.
The slow rise on the collector is simply due to the fact that a capacitor is being charged through the collector load (LED and resistor). [edit] Actual turn-off of the transistor itself is about as fast as you'll ever get with a BJT because of the rather large reverse voltage applied to the B-E junction. That sweeps carriers out of the base region resulting in turn-off even faster than you'd get by shorting the base to the emitter and very much faster than simply stopping flow of (conventional) current into the base.
This is exactly the circuit that brought me into electronics when I was about 11 or 12 years old. At that time I used Germanium transistors and lightbulbs instead of LEDs. It is also the circuit that brought me into designing and building my very first circuit board. So much things I learned at that time. Iron(III) chloride was such magic and somehow frightening thing when I saw the copper disappearing slowly on the circuit board. I even built a little wooden box to house my little light flasher and to show it to others. But the strangest thing of all is that even today I can't really explain how this circuit works, yeah! (I have always remained a hobbyist and became a software engineer instead.)
WOW. Back in 1974, whilst at school I used to build these multivibrators using a pair of bc107s and filament MES bulbs as the collector loads. The other values were exact and this really takes me back down memory lane. You can tell how old someone is by asking them what various part numbers mean.
In 1970 I built a multivibrator like this , except that it was with 2 germany PNP "AC 128" transistors. Instead of LED I employed a VW Beetle courtesy light bulb , thus it had to run slower to see light blinking. I had nearly no experience with electronics , so a friend of mine who owned a Radio\ TV repair shop taught me some lessons.
These circuits are so much more interesting, fun and informative than a 555 circuit! Bravo!
NPN transistor multivibrator was one of the first electronic circuits I ever built, both with an incandescent lamp and a LED. It was a lot of fun to see it work, though I would have to wait over a decade until I got my first scope.
The famous astable flip-flop (or multivibrator) circuit. 😁
Viewers from the digital age might understand this idea better if you build a simple astable with two gates of a 4069 hex inverter.
The slow rise on the collector is simply due to the fact that a capacitor is being charged through the collector load (LED and resistor). [edit] Actual turn-off of the transistor itself is about as fast as you'll ever get with a BJT because of the rather large reverse voltage applied to the B-E junction. That sweeps carriers out of the base region resulting in turn-off even faster than you'd get by shorting the base to the emitter and very much faster than simply stopping flow of (conventional) current into the base.
This is exactly the circuit that brought me into electronics when I was about 11 or 12 years old. At that time I used Germanium transistors and lightbulbs instead of LEDs. It is also the circuit that brought me into designing and building my very first circuit board. So much things I learned at that time. Iron(III) chloride was such magic and somehow frightening thing when I saw the copper disappearing slowly on the circuit board. I even built a little wooden box to house my little light flasher and to show it to others. But the strangest thing of all is that even today I can't really explain how this circuit works, yeah! (I have always remained a hobbyist and became a software engineer instead.)
You can build these with more than two stages and it will ripple through all of the lights.
Tomorrow a flashing Led video with a PNP and NPN transistor?
Well wouldn't ya know !!...cheers.
Опача, мультивибратор. Пытался два дня понять ю, куда щаряды там идут))
I have a video in my channel showing this configuration being used to switch two mosfet, which switch some bicycle LED sticks.
better than using an arduino to flash LEDs :)
A USAF "pinger" detector. Basic soldering course.
Weird that the modern generation would use a processor running at 1GHz with at least 2GB of memory to achieve exactly this…😜😜😜sorry kids 🤣😂🤣
Thanks 🙏👍